A Marvelous Adventure
by LLN
Summary: Xander's uncle asks her to keep an eye on a SHIELD asset and in doing so becomes part of a group that saves the world...a lot. (Xander Harris is a GIRL in this story. How that happened can be read in Beginning is the End on Twisting the Hellmouth under the author's name LLN.)
1. Chapter 1

Avengers/BtVS Pro.

Title: A Marvelous Adventure.

Author: LLN

Pairing: None. Bruce Banner/ Xander Harris Friendship.

Spoilers: All of BtVS, AtS, All the Marvel movies.

Summary: Xander's uncle asks Xander to keep and eye on a SHIELD asset and in doing so becomes part of a new group that saves the world…a lot.

Disclaimers: Buffy and Angel are owned by Joss Whedon. The Avengers, and other marvel movies are owned by Marvel Studios.

8888

February 2009

"What are you doing here, Uncle Phil?"

The question was asked by Xander Harris, the pretty dark haired girl, whom Phil thought of more like family than the people he was actually related to by blood. She was standing in the open door of the hotel, dressed in a man's white dress shirt with the sleeves rolled up to her elbows, dark colored jeans and was barefoot. She was looking tired and her brown eyes had an expression in them maker her look a lot older than the seventeen/eighteen that she resembled. Coulson could only marvel at how unchanged she was physically. At how she looked the same now as she did almost a decade ago when she graduated.

Blowing up your high school is always a memorable occasion.

Xander stepped back away from the door and walked over to the mini-bar opening it, Phil; followed her inside and closed the door. She pulled out a bottle of Jack Daniels and poured two shots handing one to Phil before tossing the other back in a quick motion. When she looked at Phil that's when he could see it more clearly…Her eyes. It was the same look that was in Romanoff's, Barton's…in his own. It was that of someone who had seen far too much…lived to hard… lost too much and had been through hell, yet… kept going.

Phil set his shot glass down on the table as Xander curled up on the black and gold striped sofa,

"I head you were at loose ends."

Xander gave a bitter laugh.

In 1999 Spike had died during the battle of Xander's graudating class. Phil remembered the blonde vampire who had worshipped the ground Xander walked on. Xander had been devastated at his death but carried on. Phil thought the girl recovered from it. Had heard about her other adventures with her friends and family about saving the world.

Then a few months ago he got a call from Jessica Harris-Giles-Rayne, Xander's mother had called Phil worried about her daughter. Spike it turned out hadn't been dead, be a captive of a government group that had brain washed Spike turning him into an assassin for them…the group had been…well from what Jessica had told him it sound like the group was a small terrorist cell for HYDRA. But Coulson knew that couldn't be possible. HYDRA had been wiped out in the forties by Captain America.

Xander had, from what Jessica said, at time been traveling the US and some other countries, helping Faith Lehane and her husband Dean, later Angel Investigations, and other assorted supernatural hunter groups. Sometimes helping Jared Parker, with his crusade to take down the Center.

And TJ O'Neill and Jack O'Neill for the last three years in a vain attempt to forget Spike. From what Jessica had told him, Too find out Spike hadn't died saving the small town from an evil man. Too find out otherwise…Now the girl blamed herself for not looking harder for the vampire. Spike, who had been so endoctorated by HYDRA that Xander had staked him to free him from the terrorist group.

"I want you to come work for me." Phil told Xander, "Work for SHIELD."

Xander frowned and rubbed her eyes, "Didn't Mom threaten to remove parts of you if you made me that job offer again?"

Coulson nodded, ten years ago, Jessica had in fact threatened to tear his balls off and feed them to him. But Jessica was so worried about her daughter, that she had been the one to ask him to make the offer to Xander. Coulson had seen the hero that Xander was all those years ago.

But Xander hadn't been ready then…or perhaps it was better said SHIELD hadn't been and maybe still wasn't ready for Xander Harris.

"I need a favor."

Xander looked up sharply, "You need a favor?"

Coulson nodded.

Xander stared at him for so long Phil was sure the girl was going to refuse then she shrugged and got a far off look on her face, "What the hell," she murmured as her eyes glowed green.

8888

May 2009, Brunete. Spain.

Bruce Banner sighed as he read the article on the back page of the newspaper in almost shouted the words in Spanish script.

'HUGE GREEN MONSTER LAST SEEN IN…'

It was accompanied by a picture of the Other Guy roaring and smashing a French tank.

'After all this time why can't they leave me alone?' Banner wondered throwing down the paper. He looked around the small bus station at all the people coming and going and never realizing the monster in their misted. His gaze stopped on a young woman with long dark braided hair, she wore a long black leather trench coat that looked like it had seen better days, a T-shirt with Catwoman on it, dark blue jeans and hiking boots.

While her clothes were dirty they were well worn. Bruce looked down at his own clothes which shown a similar condition. She was carrying a small duffle bag and she was, Banner could admit, very pretty with all the curves a woman was suppose to have where they should be but…she looked pale under her light tan and her cheek bones looked sharp as if she had missed a few more meals than she should have. She was staring at a maginze rack with a disturbed expression.

"Don't do it, Banner." He told himself as he picked up the newspaper and flipped to the front of it. The headline caught his eye, 'INTERNATIONAL WATCHER'S COUNCIL MEMBER STILL AT LARGE…'

The IWC had appeared six years ago, when a small town in California revealed that the supernatural was real via Reality TV. Vampires, Witches, Werewolves, and everything that goes bump in the night and the people who fought them, it seemed made for good TV watching. Most of the world's governments thought it was a hoax but to many people stared to come up dead from blood loss and others became missing. The governments realized it was true and that the IWC had cleaned up SunnyDale.

What really pissed of most of the governments was that the IWC was loosely affiliated with the Bristh and American government.

Banner thought the other governments were stupid for giving the IWC a hard time. The organization had been keeping the supernatural contained quite well.

Since some of its' members were in high school when the worst of the shit was going on in SunnyDale.

Banner noticed the picture on the front page of the paper; it was of a blonde woman standing between two brunettes. The brunette on the left was the same woman standing by the maginze rack!

"You are an idiot, Banner." He muttered standing up when he saw the two Spanish police officers walk in and made their way over to the coffee shop. The article never said what the young woman had done…Banner knew the look of some one hunted though. Slowly he strolled over to her stopping just behind her and whispered in her ear, "There are cops in the coffee shop."

"Where else would they be?" she whispered leaning back against him. As the two officers he warned her about came out of the shop with cups. Banner slipped an arm around her waist asking, "What bus are you on?" as he lead her back to where he had been sitting to pick up his own duffle bag. He let her go and picked up the bag.

"The 418 to Madrid. What are you…"

"It you can stand faking being my girlfriend for the bus ride it might help you avoid unwanted attention." Banner knew the police officers weren't looking for the girl but just the wrong thing could bring attention to her…and him. "I hear Madrid is nice this time of year."

The young woman nodded and entwined her fingers with his as she said, "So have I."

8888

Closing his eyes Bruce leaned back in his seat as the bus passed the Brunete city limits sign.

"Xander Harris, by the way."

Bruce opened one eye to look at the girl, "Sorry?"

"My name is Xander." She said with a sight smile. "You helped me so you should know my name at least."

To Bruce that sounded far to trusting. A lesson he learned quickly after the fourth person he tried to help betrayed him to General Ross. But something in the girl's eyes told him that a lie would not sit well with her, "Bruce Banner…" he whispered, trusting someone with his real mane for the first time years.

"It's nice to met you, Bruce." She whispered back to him before settling into her seat and closing her eyes. Bruce looked at Xander for a moment and did the same.

Xander had woken about an hour and a half ago she watched as Banner slept restlessly.

"Damn it!' she thought. It wasn't fair. The scientist had the same look in his eyes that Jared had when Xander had met the Pretender. That same hunted…haunted look. Xander wondered again for the thousandth time why, just why she let her Uncle Phil convince her to do this. It could blow up massively in her face.

Xander didn't really want to find out if she could take on a Hulk.

88888

July 2009…Somewhere in Spain

Bruce wasn't sure why Xander was still around. She could have gone her own way a long while back. No one had ever stayed…not even before the Other Guy came along in his life. When he asked Xander why she stayed she had told him, "You did me a good deed. I can't leave until I repay it."

Bruce had told Xander about the Other Guy because he had been worried about her safety and to explain why she found him naked and passed out in fields. He didn't want her hurt like Betty Ross had been.

Xander's response to that, "So, you have anger management issues. So does most of the world if you've noticed."

"Most people don't turn in to a big green monster."

"No, they become something much worse."

8888

August 2009…Still somewhere in Spain…

When Uncle Phil told Xander armies would be after Banner…She hadn't thought her uncle meant actual Armies! Also Phil didn't warn he about how much of a bleeding heart Bruce was….

'I swear! This is the last time…' Xander thought. ' The people Bruce helps end up being the ones who turn him over to the governments!' Xander growled to herself as she drove their get away vehicle out of town with Bruce passed out in the back seat.

8888

October 2009…Ireland

'Demon bounty hunters? ' Thought Bruce as he broke into the building Xander was being kept in. How was this is life again? Oh, yeah when he tested Gamma Rays on himself.

Sometimes Bruce wondered which one of them had the worst life.

November 2009…Canada

Hulk was mad… Hulk no like hurty things that hit him. Hulk roared…

A small fur covered female with glowing green…pretty green eyes…roared back…

Hulk shivered….Hulk was scared.

8888

December 2009…Africa

Bruce had never met a woman who didn't mind roughing it. Xander though seemed to like the hard conditions they sometimes had to live with. Bruce had noticed a few other odd things about Xander.

She didn't care about the same things other women her age did and if hit on by men Xander would politely rebuff them…or knock them out depending on her mood.

Bruce thought perhaps Xander preferred women until Xander told him about Spike, her lost lover. Then about Jared who Xander had a short relationship with before helping win over his childhood sweetheart.

She had drunkenly told him more about her changed timeline so she could save the world and that one of the changes to it was the fact she had a mystical sex change so she could be merged with a Primal (and perhaps demonic) Goddess. Which explained why her eyes glowed a green that was almost radioactive in color, and had fur, fangs and claws. They had yet to come against anything that Xander could not beat. Bruce knew that was only a matter of time.

8888

January 2010…Geosha.

Xander and Bruce swore to never speak of what was revealed to them on the island Kingdom ruled by Magneto and his Consort. Xander would lose what was left of her mind if she did. Because that? No, just no…

8888

March 2010…Calcutta, India.

"We are being watched." Xander said, looking out the window of their small apartment.

"Aren't we always?" Bruce muttered distractedly, they were use to being watched. It just depended on which government it was and how long it would before they were attacked again.

"Yes, by never this blatantly. " Xander shook her head, "Something is going to happen. And soon if the Street Rats are to be believed."

"Do you?" Bruce asked looking up from his laptop.

Xander shrugged, "They have yet to lie to me. Yet for the right price they will. There are saying many men in suits are asking questions."

"They have to eat somehow." Bruce said as he turned to look back at his computer screen. "And the men in suits always find us."

"Yeah, well I worry more about the Armies they bring with them." Xander said quietly.


	2. Chapter 2

Calcutta, India.

Xander watched the dark haired man followed the native Indian girl to the isolated house at the edges of the city. Xander shook her head, if she had told Bruce once she had told him a hundred times. Never take anything at face value. Sometimes Xander wondered just what went on in the good doctors head? Goddess knows he should know that by now.

Xander crept closer to the house she could make out the shadows of men surrounding it. Shadowy type men with weapons following Bruce Banner was never a good combination it always led to…property damage.

On the edge of the wind Xander could hear…

"…Should have got paid up front, Banner." Come from the scientist sardonically. Bruce had a wonderfully dry and understated sort of sense of humor at times.

Xander frowned, there were at least ten to fifteen men inching towards the house. Not exactly an army but close enough to make a platoon. It made her wonder just who sent them. No, one should come after Dr. Bruce Banner with anything less than a total army. Xander moved through the darkness pulling her battle-axe from the harness she wore on her back but she left the blade protectors on it. She didn't want to kill anyone but Xander wouldn't let these people hurt Bruce. Uncle Phil would be so disappointed in her if she did.

Xander hit the nearest black clad man in the back of his head with her axe. In the low light of the moon she could make out the S.H.I.E.L.D. emblem on his shoulder. That was odd. Normally didn't want you to know who they were or why they were there what with it being a covert-agency and all.

'I really need to check in with Uncle Phil more…' Xander thought as she took out the next three agents in the same manner as the first man. Xander could see the silhouette of a woman though the curtain covered window. Xander could hear her say, "You know, for a man who's suppose to avoid stress…you sure picked a hell of a place to settle."

Xander grabbed the next Shield agent this one was actually trying to sneak up on her. That was cute. She slammed him into a nearby tree. When she heard Bruce's response to the woman, "Avoiding stress isn't the secret."

'No, shit.' Xander thought, punching out the next agent a female this time that came too close to the house. As Xander slid closer she could hear the amused smirk in Banner's voice when he said, "You brought me to the edge of the city, smart. I…uhh, assume you have the whole place surrounded?" The bastard sounded like he was trying not to laugh Bruce knew Xander was out here and knew what she would be doing. He was mean like that.

"Just you and me…"said the woman.

Xander peaked into the window as saw the woman had bright Willow-quse hair and moved like a slayer. 'Liar, lair…' Xander thought as she ties up the next agent she knocked out. 'Bored now…' Really, Phil had said all agents went through a hell of a training course. Phil went on and on about it. Xander hoped Clint was in the trees somewhere he would be the only challenge she'd get it looked like.

"So, who are you?" Was Bruce's next question? Xander frowned at the tone of voice he used.

'Is he flirting with her?' Xander wondered?

"Natasha Romanoff."

The last five agents raised their weapons and inched closer to the house.

'Not going to happen.' Xander thought.

"You here to kill me, Miss Romanoff? Because that's just not going to work for us." Banner said softly.

For a moment Romanoff wonder why he used the word 'us' but dismissed it. The man had what was the worst case of multiply personality disorder in the history of ever. She shook her head, "I'm here on the behalf of SHIELD."

"SHIELD? How did they find me?" the doctor walked around the room looking at the different things in it.

"We never lost you." Romanoff heard rumors about an agent that was assigned to Banner but that's all they could be not even SHIELD would want someone as close as the rumor said they were to the doctor. "We've kept our distance. Even helped keep other interested parties…like a certain General off your scent."

Banner frowned, "Why?"

"Nick Fury seems to trust you. Now you need to come in."

"What if I say no."

Romanoff gave a small smile, "Then I'll persuade you."

"…And what if the Other Guy says no?"

Romanoff shrugged pulling her shawl more tightly around her shoulders, "You've been more than a year without an incident. I don't think you want to break that streak."

Banner paused in front of an old-fashion baby bassinet. With a sad smile he gave it a small push with a finger and watched as is swung back and forth before glancing up at the redheaded agent, "We don't always get what we want…"

Romanoff slowly walked up to the table between them and opened the laptop sitting on it she brought up some files then turned the computer to face Banner. Intrigued he came closer to the table, which Banner could tell made the woman ever so slightly uncomfortable but be ignored her and looked over the files.

"What is that?"

"This is the Tesseract. It has the potential to wipe out the planet."

"What does Fury want me to do? Swallow it?"

"It's been taken. They Tesseract omits a gamma signature that's too weak for us to trace. We want you to help us find it. There is no one who knows gamma radiation better than you. If there was, that's who I'd find." Romanoff told Banner plainly.

"So, Fury's not after the monster?" Banner's disbelief of that was obvious. There wasn't any secret agency or government that didn't want the monster.

"Not that he's told me."

Banner looked down and muttered, "Wants me in a cage…"

Romanoff looked confused at this change in the doctor's otherwise clam demeanor, "No one is going to put you in a…"

Banner slammed his hands down on the table narrowly missing the laptop, "Stop lying!"

At the show of temper Romanoff pulled her gun and pointed at Banner. He inhaled in surprise at how quickly the female agent moved. "I'm sorry…" He said slowly breathing out to clam himself, "That was just mean of me. I just wanted to see what you'd do. Why don't we do this the easy way? I'm a big fan of the easy way." He had put his hands up to show how Romanoff had all the power in this situation, " Where you don't use that so the Other Guy doesn't make a mess and no one ends up dead? Okay…Natasha?"

The Agent looked into Banner's eyes for a long moment before, "Stand down, we're good." Romanoff said into her earpiece, her gun steady on Banner. She wondered why he was smiling so soon after the out burst of temper he shown. Suddenly there was a crash and the black clad body of a Shield agent came flying through the open door.

'And here the night had been going so well.' Natasha thought.

"Just you and me, huh?" Banner asked amusement obvious. Natasha rolled her eyes at him. When a girl between seventeen and eighteen walked through the door saying, "Doc, unless it's a potential global catastrophe," she stopped and leaned against the doorway. "I think we should just cut our losses and go."

The girl, Natasha thought, looked like some one took a hyena's skin and placed on her, the girl's hair started black at the root to chin then turned to a light brown with black spots through out the braid the girl had it in. The skin exposed by the black tank top she wore, was covered in fur in the same shades of color as her hair, though lighter it was almost a blonde-brown in color. At her fingertips were sharp, black claws. Her dark jeans and boots were made in so they could be fought in easily. It was the girl's eyes that were the most attention grabbing, they glowed green in a way that would remind you of how a predator's eyes would.

"I try to avoid those, you know." Banner told the girl, who growled at him in response. Causing Romanoff to notice the fangs that protruded slightly over the girl's lower lip. "You took care of our friends outside, I presume?"

The girl blinked and Natasha tried not to let her amazement show when the fur morphed completely away to tanned skin and dark brown almost black hair, normal human brown eyes and the fangs vanished as well. Could the girl be a mutant?

"Yes, you know I'm never bored around you. We get to meet so many interesting people. I'm Xander Harris, by the way. And you?" the last was aimed at the red haired woman.

"Natasha Romanoff, Agent of Shield." Banner murmured to Xander causing her sighed heavily at him.

"Did you just take out all the agents out there?" Romanoff asked trying to keep the glee out of her voice. It was so rare to meet another woman who didn't mind showing just what she could do and it would explain why Banner seemed less than stressed. He had back up.

"Seems so."

Romanoff frowned, "Did you kill them?"

"I don't kill humans if I can help it."

The answer wasn't as comforting to Romanoff as it should have been. What was there to kill besides humans? Demons? She wondered on that for a second before shaking the thought away.

"Are you done here, Doc?" Xander asked Banner.

Banner shook his head.

"Come on! Doc! People like them want to put you in a cage." Xander didn't bother to hide the rage in her voice. There had been to many close calls in the last few months for Xander to be comfortable with SHIELD's sudden appearance on the scene. She had been sure she had another year before Phil was ready for Banner to come work for SWORD.

"Weren't you telling me last week I have to start trusting…"

"Oh, now you choose to listen to me!"

"Xander they need help. My help. It's the right thing to do."

Xander sighed and shook head, 'By the Gods save me from heroes!' "So when do we leave."

"She's not going!" Romanoff was almost shocked at the idea, lowering her gun. The breach of protocol alone would give Coulson an ulcer.

Banner looked thoughtful, "Mmm, then I'm not going."

Natasha nodded…wait…what? "What?"

"This as been fun and all but the Doc as spoken. See you around, Red. Or hopefully not." Xander said pushing off the doorway.

Romanoff couldn't let Banner leave and this girl had taken out all the agents sent with Natasha, she really didn't have a choice, did she? "You explain why she's there to Director Fury."

Banner nodded.

"Damn it, Bruce! Don't you have any sense?" Xander complained as she walked over to him.

The smile Banner give Xander was a fond one Romanoff thought as he said, "Come on. You've been complaining about the weather here..."

"When this comes to bite you on the ass I get to say 'I told you so', right?"

Banner nodded at Xander.

"Good, that leaves one thing." Xander said. Natasha sucked in a breath when Xander reached out and hit Banner on the side of the head. " 'That was mean? I just wanted to see what you would do?' Really, Big Guy do I have to explain what you do and don't say when some one is holding a guy on you?"

"It's not like it would hurt me." Banner muttered.

"That's not the point!" Xander hissed.

Banner then asked what the point was and Xander processed to explain that Banner was a moron.

'Why couldn't it have just been me and Banner?' Natasha wondered as she followed the bickering pair out of the house. But she knew things were about to get really interesting…


End file.
